I'm pretty sure it has nothing to do with the license or authorization.  I only mentioned that because it was the only "user visible" change from AIR to tell the two versions apart.  When I first noticed the problem I hadn't updated to the 1.0.6 version so I thought I'd try that to fix it, which is why I've seen the last two versions under JP.  I'm not sure I can even go back to pre-iLok version now.
 
Seems likely it has something to do with all the audio routing changes (since arming the track for record makes the problem go away/masks the problem).  But unless someone from Cakewalk downloads the VacuumPro demo and looks at it and figures out if it's Cakewalk or AIR's problem I suspect we are going to just have to live with it. 
 
Cakewalk support won't even tell me how Sonar fills out the Insert Synth menu on the Synth panel (so I can figure out why it's broken for me), a question I've asked them multiple times (they have just stopped replying, they must consider the issue ignorable).  I have no hope of them looking at a 3rd party VST plugin they casually broke with JP.  Any submitted ticket would just start with the blame Windows OS/Drivers/Hardware nonsense instead of actually trying it.  Cakewalk has designed their entire support system and this forum so that they can avoid actually having to fix anything.  It's engineered in.
 

I got my Air Instrument Expansion Pack, and, at least with Velvet, there is a definite delay once a track is record-enabled. This is not a recent regression: I have observed the same behavior with Sonar X1.

FWIW, I've had intermittent success avoiding the issue by running Velvet inside DDMF's Metaplugin Synth. Obviously, this is a pathetic workaround, and CW needs to fix this. No problems like this in Cubase.

You couldn't record a synth until Ipswich, so I'm not sure we are talking about the same thing.  The track I'm saying needs to be armed is the synth's audio output track.  Which until Ipswich wouldn't actually record the synth's output.
 

I've posted this issue under weird timing issue and many other have confirmed this lag on several synths...even Zeta is doing this. Others have had this issue with Machine. I have Hybrid and XPander2 and I think Hybrid also lags. I also have VST scanning issue in JP...hangs on a Wave VST - bass rider mono for some bizarre reason. I've contacted Tech Support but I don't have the time to go through further problem-solving. I installed/un-installed JP around 6 times now trying different things and each time I go back to Ipswich, both issues do not occur, so I'm staying with it for the moment and hope Cake can sort it. 

playback is fine & in time. It just seems to be when you are playing live.
I had a track with heaps of Air plugs and it plays fine but when I try to add a track, that is where I came unstuck.
 
I am back on Ipswitch & running fine; there are too many bugs in JP including huge CPU & thread issues
 
Chuck

The delay issue is fixed for the next update.
And as far as performance goes the JP issues were very specific and a workaround was available. 
However we have made major performance improvements in the next update in many areas. Probably the fastest version to date.

I have the same problem on sonar x1(d)
Major latency using air instruments (in my case with Velvet, and micro piano)
I can´t record anything on it. Also, it´s not a latency issue, all other plugins work fina, and in sonar platinum i donta have this problem , only on sonra x1
Any suggestions?